Bacterial structure and spatiotemporal distribution in a horizontal subsurface flow constructed wetland

Abstract

In this study, bacterial community structure in a horizontal subsurface flow constructed wetland (HSF-CW) planted with Phragmites australis was investigated using the 16S rRNA cloning-sequencing technique. Two layer depths were considered: the rhizosphere zone (RH) and the deep-layer zone (DL) in different sampling periods. Bacteria-specific primers 008F and 1492R were used to amplify the 16S rRNA genes and construct six clone libraries. A total of 1,284 individual sequences were used to assess the HSF-CW diversity. Phylogenetic analysis of RH and DL clone libraries shows that 41.57 and 42.17 % of the 16S rRNA sequences are affiliated with the Proteobacteria in the RH and the DL, respectively. The remaining major phylogenetic groups are Bacteroidetes, Planctomycetes, and Chloroflexi with 11.78, 9.36, and 7.6 %, respectively, in the RH and 11.38, 6.48, and 7.65 % in the DL, respectively. Minor divisions such as Verrucomicrobia, TM7, Nitrospira, and Gemmatimonadetes represented <6 % of the total sequences, while 14.2 % were unidentified Bacteria. Among the Proteobacteria, the Alphaproteobacteria subclass is represented in both locations, while the Deltaproteobacteria and Gammaproteobacteria subclasses were predominant in the RH and the DL, respectively. Results suggest that Archaea and Bacteria in the HSF-CW are the essential actors in the nitrogen cycle and that the established microbial community is efficient in nitrogen removal from wastewater.

Bacterial communities in the rhizosphere of Phragmites australis from an oil-polluted wetland

“…All soils were predominated by sequences of the class Proteobacteria. This finding is consistent with previous reports on the rhizosphere of P. australis (Li et al 2013;Bouali et al 2014b). Proteobacteria constituted 24-70% of the total sequences in our samples as well as in the rhizosphere of P. australis from other oil-free and oil-polluted wetlands (Bouali et al 2014b;Tian et al 2014).…”

“…This finding is consistent with previous reports on the rhizosphere of P. australis (Li et al 2013;Bouali et al 2014b). Proteobacteria constituted 24-70% of the total sequences in our samples as well as in the rhizosphere of P. australis from other oil-free and oil-polluted wetlands (Bouali et al 2014b;Tian et al 2014). and Leclercia were shown to degrade low and even high molecular weight hydrocarbons (Cébron et al 2011;Chandra et al 2012).…”

Influence of substrate type on microbial community structure in vertical-flow constructed wetland treating polluted river water

“…The dominance of Proteobacteria has been found in natural wetlands (Ansola et al 2014;Liu et al 2014b), wastewater CW systems (Ansola et al 2014;Bouali et al 2014;Huang et al 2013), and biofilters treating surface water (Feng et al 2013a;Liao et al 2013b). Moreover, a previous study using DGGE analysis also suggested the dominance of proteobacterial organisms in a large-scale CW system Fig.…”

“…Previous studies using traditional molecular biology approaches [e.g., denaturing gradient gel electrophoresis (DGGE), terminal restriction fragment length polymorphism (TRFLP), and clone library analysis] have greatly aided in our understanding of microbial community structure in CW ecosystem (Arroyo et al 2013;Elsayed et al 2014;Iasur-Kruh et al 2010;Morato et al 2014). A variety of factors have also been found to influence the structure of CW microbial community, such as layer depth (Bouali et al 2014;Iasur-Kruh et al 2010), operational time (Bouali et al 2014), plant type (Menon et al 2013), plant species richness , plant development (Zhao et al 2012), wastewater quality characteristics (Chang et al 2015;Zhao et al 2012), flow (Arroyo et al 2013), and water depth (Morato et al 2014). These previous studies mainly focused on CW systems treating industrial and municipal wastewater, yet microbial community in CW systems purifying polluted surface water has received little attention.…”

Dynamics of Bacterial Community Abundance and Structure in Horizontal Subsurface Flow Wetland Mesocosms Treating Municipal Wastewater

“…Ibekwe and co-workers [63] assessed the bacterial community dynamics using pyrosequencing in surface flow CWs but only with three sampling events over time. The other studies on temporal dynamics of microbial communities in HSSF CWs are mostly based on PCR-DGGE ( [64], few sampling events over time) and 16S rDNA cloning approach ( [65], three sampling events). The temporal aspect has not been taken into account in the data analysis in previous studies.…”